铜与毒死蜱复合污染对淡水绿藻的毒性效应

重金属及农药残留在水环境中被频繁检测出，其复合污染对环境生物的联合毒性有别于单因子的生物效应.以淡水绿藻为受试生物，比较分析了有机磷农药毒死蜱（Chlorpyrifos）和重金属铜的单一及复合暴露对蛋白核小球藻急性毒性、细胞通透性及抗氧化应激的影响.铜、毒死蜱72小时单一暴露对小球藻的EC₅₀分别为0.68和12.71μmol/L，藻细胞叶绿素含量随污染物浓度的增大而降低，细胞通透性随污染物浓度的增大而增强，藻细胞活性氧和抗氧化酶被显著诱导.利用相加指数法（Additive Index，AI）确定铜、毒死蜱联合暴露对小球藻急性毒性的联合作用类型为拮抗作用，这与小球藻ROS产生量及抗氧化酶等指标的显著性水平分析结果一致.

Toxiceffects of the co-exposure to Cu and chlorpyrifos toward the freshwatergreen algae

The residues of various heavy metals and pesticideshave been frequently detected in water environments, however, theirjoint toxicity is different from individual single toxicity. We evaluated the effects of single and co-exposure of organophosphorus pesticide chlorpyrifos and heavy metal Cu on acute toxicity, cellular permeability and anti-oxidative stress of freshwater green algae. The 72h-EC₅₀ for single exposure of Cu and chlorpyrifos to chlorella were 0.68 and 12.71μmol/L, respectively. The chlorophyll content of algal cells was decreased accordingly with the increasing concentration of Cu and chlorpyrifos, however, the cell permeability was increased with the higher concentrationof Cu and chlorpyrifos. The reactive oxygen species (ROS) and antioxidant enzymes were significantly induced in algae cells. As revealed by the additive index method, the joint effec of Cu and chlorpyrifos on acute toxicity wasin antagonistic mode, in consistent with the ROS production and antioxidant enzyme in chlorella vulgaris.